(a) Technical Field
The present disclosure relates to an apparatus and a method for detecting leakage in a hydrogen tank of a hydrogen fuel cell vehicle, and more particularly, to an apparatus and a method for detecting leakage in a hydrogen tank of a hydrogen fuel cell vehicle which detect leakage due to airtightness failure of a solenoid valve in a hydrogen tank of a hydrogen fuel cell vehicle and determine a leakage degree.
(b) Background Art
In a hydrogen tank which is one of the core components in a hydrogen fuel cell vehicle, hydrogen leakage is directly connected to safety of a driver and pedestrians. In particular, purity of hydrogen in the hydrogen tank is high even when a minimal amount of hydrogen is ignited and thus, the hydrogen may be easily lit causing an explosion. External leakage is immediately determined and measured by a sound generated when the hydrogen gas leaks to the outside and detection of a hydrogen concentration sensor disposed within the vehicle. However, it may be difficult to determine leakage in the hydrogen tank and leakage which is generated in a hydrogen fuel supply line or a vehicle accident results in external leakage, which may cause a more substantial accident.
In particular, the external leakage refers to leakage in which hydrogen gas, which is a vehicle fuel, is exposed from a hydrogen fuel cell vehicle to the exterior to be discharged to the atmosphere and a cause of the leakage may be separation of or damage to a pipe such as a fuel supply line. The leakage in the hydrogen tank refers to internal leakage of the hydrogen tank due to failure of a solenoid valve which is connected to an inlet of the hydrogen tank and a cause of the leakage may be failure of airtight seal in the solenoid valve. Specifically, the leakage in the hydrogen tank refers to a situation in which the hydrogen fuel gas leaks due to the leakage (e.g., leakage caused by failure of airtight seal of the solenoid valve in the hydrogen tank) of the hydrogen tank but does not leak to the exterior since the hydrogen tank is connected to the fuel supply line.
In other words, referring to FIG. 1, the leakage in the hydrogen tank refers to a phenomenon in which a normal close type solenoid valve which is directly coupled to the inlet of the hydrogen tank does not completely block a flow passage between the hydrogen tank and the fuel supply pipe and thus, the hydrogen gas in the hydrogen tank leaks into the fuel supply pipe. When only the solenoid valve of the hydrogen tank has malfunctioned or failed, there is no safety problem with the vehicle but there may be a potential danger. Therefore, a vehicle in which leakage is generated more than an allowed amount malfunctions and thus, a component requires replacement.
Further, in a state in which the leakage in the hydrogen tank is generated, when a minimal leakage is generated in a portion which is engaged with the hydrogen fuel supply line due to the car accident or a bad quality, the external leakage is continuously generated until a hydrogen tank pressure is completely exhausted. In other words, when the leakage in the hydrogen tank is generated, the hydrogen fuel gas is not exposed to the outside, but the leakage may act as a potential dangerous element, and thus it is necessary to detect the leakage in the hydrogen tank. When the external leakage is generated, the vehicle inspection may be completed in a state in which only the hydrogen fuel supply pipe is fixed but the leakage in the hydrogen tank is not fixed. Therefore, it is necessary to more accurately detect the leakage in the hydrogen tank.
The above information disclosed in this section is merely for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.